[BettyFord]

Hi my handle is BettyFord get it? And no, I'm not female.
After 250,000+km from my trusty '98 El Ghia, I recently bought from an estate, a 2009 FG Series XR6 with a genuine 115000km on the clock. I immediately had a major service done by reputable motor mechanical workshop who I've dealt with for years.
Two problems have surfaced.
1. Intermittent noisy hydraulic lifters accompanied (understandably) by the engine miss-firing. This usually rectifies itself after a few km.
2. I have heard (though not experienced it as yet), that as a preventative measure, I should fit an external air/oil cooler kit to bypass the heat exchanger. (I'm a purist, do Ford make such a beast?)
The workshop manager said he had added a "lifter/tappet" oil additive, and the issue should resolve itself within time.
He also suggested, rather than get a bypass kit installed, fit a new radiator, as the problem had been resolved by Ford.
Am I being led up the garden path? Any suggestions/threads would be most appreciated. Thank you.